Studies show virus can survive and replicate in storage for up to nine months after initial outbreak

Researchers at the University of Manitoba’s National Centre for Livestock and the Environment hope to provide swine producers with information to help prevent outbreaks of porcine epidemic diarrhea (PEDv) in their herds, according to a Farmscape interview today.

The virus, which is transmitted by infected feces, can cause severe dehydration and diarrhea in swine, according to the Government of Manitoba.

While older animals can recover, “the virus is generally fatal in very young animals,” the government website states.

The researchers studied the survivability and infectivity of PEDv in earthen manure storages (EMS) on two infected farms in Manitoba. They published their results in Frontiers in Microbiology in 2016.

The study revealed that the virus “could survive up to nine months in the infected EMS after the initial outbreak in the farm.”

Weeks after the infected manure was added to the EMS, researchers found evidence suggesting that the virus had replicated. While no additional infected manure had been introduced into the EMS, samples revealed elevated levels of PEDv.

This finding suggests that EMS may contain alternative hosts for PEDv, the journal article stated.

However, samples from the top layer of the EMS exhibited low levels of the virus. PEDv present in this layer was mostly non-infective.

These results suggest that “environmental factors, such as UV and sunlight, could diminish the replicability and infectivity of the virus.”

So, producers could potentially reduce the presence and infectivity of PEDv on their operations through frequent agitation of their EMS, the article stated.

After completing this study, the researchers worked on a project to determine whether the virus could survive in soils after farmers applied PEDv-contaminated manure to land, Christine Rawluk, research coordinator with the National Centre for Livestock and the Environment, said in the Farmscape interview.

Researchers recently finished the field investigations, which revealed “detectable levels of the virus in soil samples collected three weeks after surface applications,” Rawluk said.

However, the team did not assess the virus infectivity during this study.

“Future research will examine the survivability and infectivity (of PEDv) when infected manure is applied to different soil types under different climate conditions,” she said.

“We still need to … determine the potential of soil to become a vector for spreading this disease.”